This invention concerns a method for the removal of at least one heavy metal, e.g., arsenic, lead, tin and the like, from water in which it is dissolved, by the precipitation of a salt thereof in multiple steps. More particularly, it concerns a multi-stage process for the removal of one or more heavy metals from contaminated water wherein the metal is precipitated from solution in the form of a salt and the filtrate reprocessed one or more times at progressively higher pH to further precipitate metal therefrom. The process is useful for the treating of industrial, surface and underground wastewater to produce potable water and solid metal salts which may be reused for industrial purposes, such as copper arsenate to make wood preservatives.